Typically, ink jet printers draw ink from substantially rigid disposable cartridge-type ink containers having collapsible inner sealed bags which provide a reservoir of ink. As shown in FIG. 1, a disposable ink container 10 is inverted and positioned over a piercing barb assembly 11, having an upstanding needle 12, of an ink-jet style printer 27. When ink container 10 is manually urged toward barb assembly 11, needle 12 pierces a frangible grommet 13 to access the reservoir of ink. During use, a slidable primer rod 14 including a plunger 28 gravitationally assists ink bag collapse which facilitates movement of ink toward needle 12 and reduces ink starvation (FIG. 2).
FIG. 1 illustrates that disposable ink container 10 includes a rigid cylindrical cup member 15 having a circumferential lip portion 16 which defines a cup opening 18. An ink retaining bag 17, having an open edge portion 19 defining bag opening 20, is received in a cup recess 21 in an orientation such that bag opening 20 coincides with cup opening 18. Open edge portion 19 of bag 17 is distended to an open position by folding the flexible walls of bag 17 over the circumferentially extending lip portion 16.
Subsequently, once cup member 15 is oriented in a manner such that cup opening 18 and bag opening 20 are facing upwardly, jet ink is deposited into bag interior portion 22 to retain ink therein and form ink reservoir 23. A thin substantially rigid washer 24 is then seated over lip portion 16, having the folded over bag walls therebetween, to cover bag opening 20. As shown in FIGS. 1 and 2, the bag walls are pinched between lip portion 16 and the snap-fit container cap 25 proximate open edge portion 19 to enhance sealing. Rigid washer 24 includes a centrally positioned aperture 26 which provides a passageway to access stored ink reservoir 23. A comparatively thick grommet washer 13 is sandwiched between a snap-fit container cap 25 and rigid washer 24 which cooperate to seal bag interior portion 22 from the environment. A needle receiving slot 29 is provided in container cap 25 which is aligned with needle receiving aperture 26 of washer 24. Container cap 25 is formed and dimensioned to lockably snap on to and mate with lip portion 16 of cup member 15 to not only hermetically seal bag opening 20, but washer aperture 26 as well. Hence, cap 25 must induce sufficient sealing pressure against both rigid washer 24 and grommet 13 to prevent leakage. Further, container cap 25 must sufficiently grip lip portion 16 so as not to inadvertently separate and so that the flexible bag wall provides an adequate gasket therebetween.
While these assemblies have been adequate to supply and store jet-ink, several problems are inherent with these configurations. For example, fabrication has proven rather tedious, time consuming and costly. In addition, leakage of ink from retaining bag 17 is frequent as container cap 25 often does not properly mate with lip portion 16. As a result, the seal integrity is compromised and is no longer impervious. Further, because of the snap-fit nature of container cap 25, the gasket-type seal provided by the flexible bag 17 is often breached so that leakage occurs around the joints thereof. Moreover, once the ink reservoir is depleted, the whole container 10 is disposed of which constitutes an enormous material waste. Finally, to access ink reservoir 23, needle 12 must pierce through frangible grommet 13 at a location directly adjacent washer aperture 26, which cannot be seen. Accordingly, needle 12 can be damaged when alignment is improper and needle 12 is forced against rigid washer 24.